<template>
  <view>
    <!-- 搜索 -->
    <view class="search-box">
      <my-search-bar  placeholder='搜索一下' bgColor='#c00000'></my-search-bar>
    </view>
    <!-- 列表 -->
   <view class="scroll-view-container">
     <!-- 一级左边列表 -->
     <view class="left-scroll-view">
      <scroll-view scroll-y :style="{height:h+'px'}">
        <view :class="['left-scroll-view-item',index===activeIndex?'active':'']" :scroll-top='scrollTop' v-for="(item,index) in categories" :key='item.cat_id' @click="toggle(index)">
           <text>{{item.cat_name}}</text>
        </view>
      </scroll-view>
     </view>
      <!-- 右边列表 -->
      <scroll-view scroll-y class="right-scroll-view" :style="{height:h+'px'}">
        <view v-for="subitem in level2List" :key='subitem.cat_id'>
          <!-- 二级列表 -->
          <view class="cate-lv2-title">/ {{subitem.cat_name}} /</view>
          <!-- 三级列表 -->
          <view class="cate-lv3-list" >
           <navigator :url="'/subpkg/goodList/index?cid='+item.cat_id" class="cate-lv3-item" v-for="item in subitem.children" :key="item.cat_id">
             <image
             :src="item.cat_icon"
              mode="scaleToFill"
             />
            <text>{{item.cat_name}}</text>
           </navigator>
          </view>
        </view>
      </scroll-view>
   </view>
  </view>
</template>
<script>
    export default {
      data() {
        return {
          categories: [],
          activeIndex: 0,
          h:0,
          scrollTop:0
        }
      },
      onLoad(){
        this.getListData()
        this.getHeight()
      },
      computed:{
       level2List(){
          if(this.categories.length>0){
            return this.categories[this.activeIndex].children
          }else{
            return []
          }
       }
      },
      methods:{
        async getListData(){
          const res=await uni.$request({
            url:'categories'
          })
          if(res.meta.status===200){
           this.categories=res.message
          }
          
        },
        getHeight(){
         this.h=uni.getSystemInfoSync().windowHeight-50
        },
        toggle(index){
          this.activeIndex=index
          this.scrollTop=this.scrollTop===0?1:0
        }
      }
    }
</script>
<style lang="scss" scoped>
.search-box {
  // 设置定位效果为“吸顶”
  position: sticky;
  // 吸顶的“位置”
  top: 0;
  // 提高层级，防止被轮播图覆盖
  z-index: 999;
}
.scroll-view-container {
  display: flex;


  .left-scroll-view {
    width: 240rpx;


    .left-scroll-view-item {
      line-height: 60px;
      background-color: #f7f7f7;
      text-align: center;
      font-size: 12px;


      // 激活项的样式
      &.active {
        background-color: #ffffff;
        position: relative;


        // 渲染激活项左侧的红色指示边线
        &::before {
          content: ' ';
          display: block;
          width: 3px;
          height: 30px;
          background-color: #c00000;
          position: absolute;
          left: 0;
          top: 50%;
          transform: translateY(-50%);
        }
      }
    }
  }


  .right-scroll-view {
    .cate-lv2-title {
      font-size: 12px;
      font-weight: bold;
      text-align: center;
      padding: 15px 0;
    }
    .cate-lv3-list {
      display: flex;
      flex-wrap: wrap;


      .cate-lv3-item {
        width: 33.33%;
        margin-bottom: 10px;
        display: flex;
        flex-direction: column;
        align-items: center;


        image {
          width: 60px;
          height: 60px;
        }


        text {
          font-size: 12px;
        }
      }
    }
  }
}
</style>